Improving Fish Passage on the White River: Operations, Monitoring, Modifications, and Maintenance

Forming part of the Puyallup River Basin near Mount Rainier, the White River has long played a critical role in supporting salmon and steelhead populations in western Washington. Yet since the mid-20th century, the river’s natural connectivity has depended on engineered solutions around Mud Mountain Dam (MMD) — a major flood-control structure operated by the U.S. Army Corps of Engineers.

While the dam has protected the lower White and Puyallup valleys from over $300 million in flood damages and safeguarded roughly 400,000 people, maintaining reliable fish passage with new pioneer species arriving in large numbers has remained an ongoing technical and operational challenge.

Thanks to recent modernization efforts, that challenge is being met with innovation and persistence. Following NOAA Fisheries’ 2014 Biological Opinion, the Corps completed a new, state-of-the-art fish collection facility in 2020, designed to meet modern passage criteria and improve survival for ESA-listed Chinook and steelhead.

The current system — including an upstream barrier, trap, and haul operation six miles below the dam — continues to evolve through active monitoring, adaptive management, and co-management with the Muckleshoot Indian Tribe and Puyallup Tribe of Indians, ensuring that fish passage performance, facility maintenance, and operational strategies keep pace with biological and hydraulic realities.

Event Details

Date: Wednesday, December 3
Time: 12:00 PM – 1:00 PM Pacific Time

Join our speakers Casey Butcher and Nathan Malmborg for a presentation on Improving Fish Passage on the White River: Operations, Monitoring, Modifications, and Maintenance. They will discuss the Corps’ approach to ongoing system optimization, including:

• Data-driven maintenance practices
• Operational coordination for upstream and downstream passage
• Lessons learned from continuous performance monitoring